Kinematics of the ligamentous unstable elbow joint after application of a hinged external fixation device: a cadaveric study

We studied the kinematics of 8 ligamentous unstable elbow joint preparations after application of the Orthofix elbow external fixation device. Valgus, varus, external rotatory, and internal rotatory load tests were performed in lateral collateral ligament (LCL)-deficient and LCL/medial collateral ligament (MCL)-deficient joints. After placement of the fixator, the mean extension decreased significantly to 19.5 degrees +/- 7.2 degrees in the LCL-deficient joint and to 19.1 degrees +/- 6.6 degrees in the LCL/MCL-deficient joint compared with the mean extension of the intact joint, which was 10.5 degrees +/- 4.2 degrees. After application of the fixator, valgus displacement was significantly decreased by 4.0 degrees +/- 3.4 degrees in the LCL-deficient joint and by 3.6 degrees +/- 3.3 degrees in the LCL/MCL-deficient joint compared with the intact joint. External rotatory displacement was significantly decreased in the LCL-deficient joint by 4.9 degrees +/- 3.7 degrees and in the LCL/MCL-deficient joint by 5.0 degrees +/- 4.7 degrees. Internal rotatory displacement was significantly decreased by 3.3 degrees +/- 2.7 degrees in the LCL-deficient joint, but it was not significantly changed in the LCL/MCL-deficient joint. The Orthofix elbow external fixator guided elbow motion to a more varus position compared with the intact elbow and decreased the range of motion of the joint, constraining mainly extension. We conclude that the fixator stabilized the ligamentous unstable elbow joint efficiently but at the expense of changes in the normal motion pattern.     

Lack of awareness of treatment failure among HIV-1-infected patients in Guinea-Bissau – a retrospective cohort study

Introduction

With more people receiving antiretroviral treatment (ART), the need to detect treatment failure and switch to second-line ART has also increased. We assessed CD4 cell counts (as a marker of treatment failure), determined the rate of switching to second-line treatment and evaluated mortality related to treatment failure among HIV-infected patients in Guinea-Bissau.

Methods

In this retrospective cohort study, adult patients infected with HIV-1 receiving ≥6 months of ART at an HIV clinic in Bissau were included from June 2005 to July 2014 and followed until January 2015. Treatment failure was defined as 1) a fall in CD4 count to baseline (or below) or 2) CD4 levels persistently below 100 cells/µL after ≥6 months of ART. Cox hazard models, with time since six months of ART as the time-varying coefficient, were used to estimate the hazard ratio for death and loss to follow-up.

Results

We assessed 1,591 HIV-1-infected patients for immunological treatment failure. Treatment failure could not be determined in 594 patients (37.3%) because of missing CD4 cell counts. Among the remaining 997 patients, 393 (39.4%) experienced failure. Only 39 patients (9.9%) with failure were switched from first- to second-line ART. The overall switching rate was 3.1 per 100 person-years. Mortality rate was higher in patients with than without treatment failure, with adjusted hazard rate ratios (HRRs) 10.0 (95% CI: 0.9–107.8), 7.6 (95% CI: 1.6–35.5) and 3.1 (95% CI: 1.5–6.3) in the first, second and following years, respectively. During the first year of follow-up, patients experiencing treatment failure had a higher risk of being lost to follow-up than patients not experiencing treatment failure (adjusted HRR 4.4; 95% CI: 1.7–11.8).

Conclusions

We found a high rate of treatment failure, an alarmingly high number of patients for whom treatment failure could not be assessed, and a low rate of switching to a second-line therapy. These factors could lead to an increased risk of resistance development and excess mortality.     

Impulse-forces during walking are not increased in patients with knee osteoarthritis

Background Impulsive forces in the knee joint have been suspected to be a co-factor in the development and progression of knee osteoarthritis. We thus evaluated the impulsive sagittal ground reaction forces (iGRF), shock waves and lower extremity joint kinematics at heel strike during walking in knee osteoarthritis (OA) patients and compared them to those in healthy subjects.

Subjects and methods We studied 9 OA patients and 10 healthy subjects using three-dimensional gait analyses concentrated on the heel strike. Impulse GRF (iGRF) was measured together with peak accelerations (PA) at the tibial tuberosity and sacrum. Sagittal lower extremity joint angles at heel strike were extracted from the gait analyses. As OA is painful and pain might alter movement strategies, the patient group was also evaluated following pain relief by intraarticular lidocaine injections.

Results The two groups showed similar iGRF, similar tibial and sacral PA, and similar joint angles at heel strike. Following pain relief, the OA patients struck the ground with more extended hip and knee joints and lower tibial PA compared to the painful condition. Although such changes occurred after pain relief, all parameters were within their normal ranges.

Interpretation OA patients and healthy subjects show similar impulse-forces and joint kinematics at heel strike. Following pain relief in the patient group, changes in tibial PA and in hip and knee joint angles were observed but these were still within the normal range. Our findings make us question the hypothesis that impulse-forces generated at heel strike during walking contribute to progression of OA.     

Root resorption diagnosed with cone beam computed tomography after 6 months of orthodontic treatment with fixed appliance and the relation to risk factors

Objectives:To investigate root resorption after 6 months of active orthodontic treatment and its relation to possible risk factors.Materials and Methods:Ninety-seven patients (10–18 years) with a Class I malocclusion and crowding treated with fixed appliance and premolar extractions were examined with cone beam computed tomography before and after 6 months of active treatment. The exposure covered all teeth from first molar to first molar in both jaws. The Malmgren index was used to evaluate the degree of root resorption. Irregular root contour (score 1) was seen in most teeth already before active treatment, and therefore resorptions were registered only as score 2 (<2 mm, minor resorption) or higher.Results:Minor root resorption was noted in 10% of the patients and severe root resorption, >2 mm (score 3) was found in four patients. Root resorption was more frequently seen in the upper jaw, especially the incisors. There was no statistically significant correlation of root resorption with any of the selected risk factors.Conclusions:After 6 months of treatment, clinically significant resorption was diagnosed in 4% of the patients, ie, in 96% of the patients the radiographic examination did not reveal any significant information. The selected risk factors did not have any impact on the amount of resorption after 6 months of active treatment.     

The roles of acute and chronic pain in regression of sensory analgesia during continuous epidural bupivacaine infusion

The purpose of this study was to investigate whether regression of sensory analgesia during constant epidural bupivacaine infusion was different in postoperative patients with acute pain than in patients with chronic nonsurgical pain. Sensory levels of analgesia (to pinprick) and pain (on a five-point scale) were assessed hourly for 16 hours during continuous epidural infusion of 0.5% plain bupivacaine (8 ml/hr) in 12 patients with chronic nonsurgical pain and in 30 patients after major abdominal surgery performed under combined bupivacaine and halothane--N2O general anesthesia. No opiates were given. If sensory analgesia decreased more than five segments from the initial level or if the pain score reached 2 (moderate pain), the patient was removed from the study. Initial levels of sensory analgesia after loading doses of 21.8 +/- 0.5 and 19.3 +/- 0.8 ml bupivacaine 0.5% were similar (T3.8 +/- 0.3 and T3.8 +/- 0.5) in the surgical and chronic pain patients, respectively (mean +/- SEM). Of the surgical patients, only 4 of the 30 (13%) maintained the initial level of sensory analgesia, and a pain score below 2 throughout the study compared with 7 of the 12 patients with chronic pain (58%) (P less than 0.01). Mean duration of sensory blockade was significantly longer (P less than 0.005) in the patients with chronic pain than in surgical patients (13.1 +/- 1.2 and 8.5 +/- 0.7 hours, respectively). Thus, surgical injury hastens regression of sensory analgesia during continuous epidural bupivacaine infusion. The underlying mechanism remains to be determined.     

Bakterien als Ursache allergischer Asthmaanfälle (Versuche mit Keimen aus der Klebsiella-Gruppe)

Zusammenfassung Keime der Klebsiella-Gruppe, Typ 2, in vollsynthetischem eiweißfreiem Nährmedium gezüchtet, eignen sich zur direkten Sensibilisierung von Meerschweinchen sowie zur nachfolgenden Provokation von Asthmaanfällen und anaphylaktischem Schock.Zur Sensibilisierung wurden Keime verwandt, die bei 60° C mit Phenol, Formol oder Ultraschall abgetötet worden waren. Asthmaanfälle konnten durch Inhalation von abgetöteten, aber auch von lebenden Keimen ausgelöst werden. Die Asthmabereitschaft blieb mehrere Monate lang bestehen. Die Anfälle können durch N-Isopropylnoradrenalin zum Verschwinden gebracht werden. Im Grundsätzlichen entsprachen sie Asthmaanfällen, die durch Hühnereiweiß bedingt waren. Unterschiede gegenüber dem Hühnereiweißasthma zeigten sich in geringerer Schockbereitschaft, vermehrter Dyskrinie und dem gelegentlichen Auftreten von Spätreaktionen.Das anaphylaktogene Klebsiella-Antigen ist ein unlöslicher Bestandteil des Bakterienleibes, vermutlich kommt es in der Grenzphase vor.Die Untersuchungen erbringen den tierexperimentellen Beweis, daß Bakterien alsprimäres Allergen Asthma hervorrufen können.FräuleinTrude Schulte danken wir für die wertvolle Mitarbeit. Die Untersuchungen wurden durch ERP-Mittel ermöglicht, für deren Vermittlung wir Herrn Prof. Dr.Hagen, Bundes-Innenministerium, danken.